CBE tripping precautions: For most applications, CBE should not trip. In the event of a malfunction, it is impossible to forcibly shut it down. IEC 934 includes appropriate definitions for definite no trip and no cycle trip designs. If the closed command is maintained, there will definitely be no tripping type contacts that will remain open. In the same situation, contacts without cyclic tripping type are repeatedly closed and reopened. For applications that do not require special consideration of short-circuit protection, the ideal choice is a hot start circuit breaker. On the other hand, when operating at a very low speed and very fast for sustained overload conditions, only electromagnetic circuit breakers must be used.

Comparison between CBE and fuses

Traditionally, fuses provide circuit protection from the AC line voltage level all the way to the low-voltage printed circuit board level. However, in the field of low-voltage overcurrent protection, solid-state devices such as CBE and PTC resistors are gaining recognition. Solid state devices are not suitable for all applications because as current limiters, they cannot provide the positive physical isolation that is sometimes required by major standard organizations. For high reliability, high-performance systems, or low-voltage systems with strict safety requirements, CBE remains an increasingly viable alternative to fuses and other circuit protection devices, despite increased costs. A common misconception is that CBE is too large in size and/or too expensive. However, CBE comes in various types and packages, including miniature models that can be installed on micro PC boards (see Figure 2). In terms of its size, CBE has extremely high interrupt capability. This is the ability to switch high currents without causing a fire or damaging equipment. The CBE shown in Figure 2 occupies an area of 28 x 9 mm and can switch to 50 A at least and up to 3 times at 125 Vac. Although the unit cost of CBE is higher than that of fuses, the cost savings brought by using CBE become evident when calculating the overall cost of device ownership. Compared to fuses, CBE's resettability and other functions may have a significant impact on safety and reduce system downtime. When specifying CBE, designers have multiple types to choose from, each with a certain rated current, trip characteristics, installation style, and value-added features. To protect the circuits of printed circuit boards from catastrophic faults caused by overcurrent and short circuits, it is usually recommended to use thermal and thermomagnetic types

The hot CBE utilizes the heating effect of bimetallic elements to provide an overcurrent detection mechanism. Once the circuit breaker trips, the power is cut off until the device is reset. After the thermal circuit breaker is tripped and cooled, it will reopen, causing it to cycle out. CBE suppliers are now designing their equipment to eliminate this impact, and international safety and standards organizations provide proof of equipment integrity within the approved scope of such products. For circuits that require rapid response protection against excessive current, the thermal magnetic CBE has an additional solenoid element that provides very high tripping characteristics. On the other hand, pure magnetic CBE operates quickly and is sensitive to small overload currents, but its tripping characteristics can be modified by adding hydraulic damping to delay tripping. By combining different tripping mechanisms, the load characteristics of the system can be matched with the tripping characteristics of CBE. By actually eliminating troublesome tripping, CBE is superior to other circuit protection devices. False alarms are almost as expensive and destructive as real faults. In order to further reduce downtime, many CBEs now include features such as status signals or visual trip indications to accelerate the speed of fault detection. And, of course, because CBE is reset, there is a need for inventory spare parts.

What is a device circuit breaker?

Equipment circuit breakers (CBE) are different from other protective devices such as fuses or miniature circuit breakers (MCBs). The IEC 934 standard of the International Electrotechnical Commission describes CBE as an electromechanical switchgear used to protect circuits within electrical equipment in the event of overload. This description acknowledges that the sensitivity of the device required for relatively small overload currents that may occur is different from that of fuses and MCBs that are misnamed and frequently used incorrectly. IEC 934 is a European driven standard, but it is also associated with manufacturers of committees that include all famous North American circuit breakers. IEC 934 is applicable for rated currents up to 125 A
Circuit breakers with rated voltages up to 440 Vac or 220 Vdc. CBE provides overload and limited short-circuit protection, which can closely match the operational characteristics of the components, equipment, or systems to be protected. Fuses cannot effectively distinguish between overload and short circuit situations. However, many devices still need to distinguish between transient surges and sustained fault currents. Only CBE can provide two types of protection.